Letrozole Co-Treatment in Infertile Women 40 Years Old and Older Receiving Controlled Ovarian Stimulation and Intrauterine Insemination

Abstract

Controlled ovarian hyperstimulation (COH) using the gonadotropin, follicle stimulating hormone (FSH), combined with IUI (COH-IUI) achieve higher pregnancy rates (PR) than IUI alone in treatment of infertile older women. Letrozole, a highly potent nonsteroidal aromatase inhibitor, has been increasingly used in COH protocols. This retrospective case-control study investigated the effect of adding letrozole to FSH in COH-IUI cycles in a population of infertile women at or more than 40 years old. Two comparison groups were used: group I (n = 90) was comprised of infertile women who received letrozole combined with FSH and group II (n = 69) included patients who received FSH alone (n = 69). The primary study outcome was primary rate (PR). Secondary outcomes examined included mature follicles and serum levels of estradiol (E 2 ), progesterone (P), luteinizing hormone (LH), endometrial thickness, and rates of cycle cancellation. No significant difference in PR was found between the letrozole-FSH co-treatment group and the FSH alone group. Compared with the FSH alone group, the letrozole co-treatment group had significantly fewer cancelled cycles and more completed cycles. The serum E 2 levels and the number of mature follicles were significantly higher in the FSH only group than in the combined letrozole-FSH group (P < 0.001 for both). On cycle day 7, the serum level of LH was significantly higher in the letrozole co-treatment group (P < 0.001); LH serum levels were similar in both groups on all other cycle monitoring days. Serum P levels were significantly higher in the FSH alone group compared with the letrozole co-treatment group on the day of human chorionic gonadotropin administration (P < 0.001). These findings show that letrozole co-treatment has several beneficial modulator effects on gonadotropin-stimulated cycles without a negative impact on PR. The investigators believe that the addition of letrozole to gonadotropins in combination with the COH-IUI protocol could be a promising initial option for older infertile women.